This application focuses on a wireless communication receiver for ultra low power (e.g. less than 100 micro-watts (μW)) applications, such as can be used in wireless sensor networks (WSN) or wireless body networks (WBN).
An example of a low power RF receiver circuit used as a wake up receiver (WuRx) is described in IEEE 2007 Custom Integrated Circuits Conference (CICC), “A 65 μW, 1.9 GHz RF to Digital Baseband Wakeup Receiver for Wireless Sensor Nodes”, by N. Pletcher, S. Gambini, J. Rabaey, p 539-p 542. This receiver circuit uses a tuned RF architecture with a bulk acoustic wave (BAW) filter to reduce out-of-band interference, a front end amplifier (FEA) to amplify the RF input signal, and an envelope detector to down-convert the on-off-keying (OOK) RF signal to baseband. A disadvantage of this architecture is that the noise of the envelope detector which essentially determines the sensitivity of the circuit needs to be entirely compensated by high gain of the front end amplifier. This consumes a lot of power.